1. Field of the Invention
The present invention relates to an object, a method, or a manufacturing method. The present invention relates to a process, a machine, manufacture, or a composition of matter. In particular, one embodiment of the present invention relates to a semiconductor device or a method of manufacturing the semiconductor device.
In this specification and the like, the term “semiconductor device” means all devices that can operate by utilizing semiconductor characteristics. An electro-optical device, an image display device (also referred to as a display device), a semiconductor circuit, a light-emitting device, a power storage device, a memory device, or an electronic device include a semiconductor device in some cases.
2. Description of the Related Art
A technique in which a transistor is formed using a semiconductor layer has attracted attention. The transistor is used in a wide range of electronic devices such as an integrated circuit (IC) and a display device. As semiconductor materials applicable to the transistor, silicon-based semiconductor materials have been widely used, but oxide semiconductors have attracted attention as alternative materials.
Formation of an oxide semiconductor film having crystallinity has been studied. For example, according to Non-Patent Document 1, an InGaO3(ZnO)5 thin film is formed by a PLD method over a single crystal thin film of ZnO formed over a YSZ substrate, and subjected to heat treatment at 1400° C. to have a single crystal structure. According to a technique disclosed in Patent Document 1, a single-component oxide semiconductor layer is formed over a substrate; crystal growth is carried out from a surface to an inside by heat treatment at 500° C. or higher and 1000° C. or lower, so that the single-component oxide semiconductor layer includes a single crystal region; and a multi-component oxide semiconductor layer including a single crystal region is formed over the single-component oxide semiconductor layer including a single crystal region. The multi-component oxide semiconductor layer formed in this manner is used for a transistor.